Visionaries have seen the future, and it will be lived in attached and/or stacked housing: high-rises, condos, co-ops and townhomes.

Urban attached housing is greener in every way, especially when it sits along a transit line. It concentrates energy-consuming humans in a smaller area, in buildings that conserve energy, save space, and put the humans in close proximity to their needs.

But this brave new world will create its own set of issues. Lots of Americans are used to spreading out and NOT used to listening to Party Man next door cranking the stereo until 4 a.m.

For the many Americans who either grew up in or now live in detached housing, moving to a stacked unit and a shared ownership system would be an extreme lifestyle change.

A new book, New Neighborhoods: The Consumer's Guide to Condominium, Co-op and HOA Living (Emerald Book Co., $16.95), by Gary A. Poliakoff and Ryan Poliakoff, addresses the things new, attached-home owners might need to know. And while most of the book concentrates on shared ownership situations, it does also address some of the issues faced by subdivision homeowners associations, too.

If you are considering purchasing in a condo building, it's worth your time to find out exactly what you are getting into. For one thing, what exactly are you buying? Depending on your paperwork, you may own only the space inside your walls on your own, but have a common ownership of common areas such as the lobby, the walls, and the grounds around the building.

"In common interest ownership," write the Poliakoffs, "every owner will ultimately be responsible for both the good times and the bad times, with very little financial flexibility."

As an example, if you live in a single family home and the concrete patio is cracked, you can decide when you will repair it and how well the job gets done.

In a condominium building, that sort of flexibility does not exist. Condo associations are required to keep the building in good repair and will have to fix the concrete and bill their members, if funds are not available.

The book also spends a little ink on the issue of noise -- considered one of the most prevalent complaints about attached living. Noise complaints have only gotten worse since hardwood floors have enjoyed a renaissance. Carpet was quieter and would muffle sounds. There is no law that says your upstairs neighbor cannot pace the floor between 2 and 6 a.m., but you might have a case if your neighbor's dog barks for six hours a day.

New Neighborhoods does a good job of explaining all the legalese a new condo dweller will encounter, and puts their rights and responsibilities in plain English. Occasionally it veers into the obvious or gets a little too cute but, for the most part, it would be a good guide for newcomers to attached living. This book, or something like it, should be required reading for association board members, and would make a good housewarming gift as well. It does help to know your rights.

Last week's column on reverse mortgages, a financial solution for some senior citizens, generated some quick feedback.

Sharon Johnson, who wrote Taking the Mystery out of Nursing Home Medicaid, a book on Medicaid eligibility, points out that there is a legal technique called a Miller Trust (though it also goes by other names), by which seniors can protect their Medicaid eligibility.

"Your article about reverse mortgages was spot-on," she wrote. "Medicaid eligibility is difficult to attain, and it's getting harder. I've seen people create revocable living trusts, thinking that they're protected for Medicaid purposes. Not so. Anyone considering a reverse mortgage would be well advised to meet with an elder law attorney prior to completing the transaction."

Johnson sent me a lot of information about how Miller Trusts can help seniors protect their income while applying for Medicaid. In a nutshell, it's complicated, and "not something to attempt on your own."

Yvette L. had a different take on the column. She thinks I was scaring old people away from what could be an appropriate tool for some.

"You are looking at reverse mortgages through too narrow a prism if you have come to such a negative opinion," she wrote. Regarding the current troubles that reverse mortgages have faced, she said, "This current real estate environment is an anomaly, wouldn't you agree."

Regarding alternative programs, such as those through municipalities, she said, "These programs are good alternatives when you can take advantage of them and everyone should inquire as to their eligibility, but they are usually oversubscribed. Many may have multi-year waiting lists -- which will not help if you need a furnace or boiler or roof."

And regarding the hopes of many seniors to leave their home or its value to their children, she said, "Most children don't want the house and may be currently providing monthly assistance to their parents when they need those funds to keep their own household afloat."

Like I said, it's complicated. I don't have a negative opinion on reverse mortgages, I have just recently come to understand that they are not a simple answer to financial difficulties. I know one couple who signed away their equity so they can take frequent vacations. That's not a good strategy for most seniors.

I like Johnson's advice: Before you sign a reverse mortgage, talk to an attorney who specializes in elder law.